The present invention relates to a single regulation power supply with load compensation of an auxiliary voltage output.
Multiple output power supplies are well known and widely used in the electronic industry.
The most sophisticated and expensive of these prior art power supplies provide independent regulation of each output; in other cases they provide precise voltage regulation of the main output, but with some consequential regulation effects on auxiliary outputs, and further provide post regulation circuits for the auxiliary outputs to achieve the desired regulation level.
In several instances, it is necessary to limit the cost of these power supplies; to this end voltage regulation is provided for only the main output and no post regulation is provided for the auxiliary outputs.
In order to minimize "cross regulation" (a deceptive term which indicates more than regulation), the variations caused in an auxiliary unregulated output by load variation of the main regulated output, an arrangement is often used in which an auxiliary voltage of an auxiliary output is generated as the sum of the regulated main voltage output and an unregulated secondary voltage output.
In this manner, a fraction of the auxiliary voltage is precisely regulated and unaffected by load changes in the main or auxiliary outputs, and "cross regulation" is reduced at some extent.
An example of such multiple output power supplies is discussed in the article "A Multiple Output Converter with Load Compensated Gain to Achieve Stability Under Light or No Loading Conditions" by K. H. Kuster, published in Intelec, International Telecommunication Energy Conference, Washington, D.C. U.S.A., 3-6 Oct. 1982, pp. 125-130.
Nevertheless, the effect of load changes in the auxiliary outputs of these prior art power supplies appears to be unavoidable unless some form of post regulation is utilized with the main output regulation.